.

Saturday, December 8, 2007

U of Calgary biology professor Peter Dunfield and colleagues describe the new methane-eating microorganism, Methylokorus infernorum , found in the geothermal field known as Hell’s Gate, near the city of Rotorua in New Zealand. It is the hardiest “methanotrophic” bacterium yet discovered.

“This is a really tough methane-consuming organism that lives in a much more acidic environment than any we’ve seen before,” said Dunfield. “It belongs to a rather mysterious family of bacteria (called Verrucomicrobia) that are found everywhere but are very difficult to grow in the laboratory.”

Methanotrophic bacteria consume methane as their only source of energy and convert it to carbon dioxide during their digestive process. Methane (commonly known as natural gas) is 20 times more potent a greenhouse gas than carbon dioxide and is largely produced by decaying organic matter. Scientists have long known that vast amounts of methane are produced in acidic environments, not only geothermal sites but also marshes and peat bogs. Much of it is consumed by methanotrophic bacteria, which serve an important role in regulating the methane content of the world’s atmosphere.

Distinct groups corresponding to broad microbial taxa can be delineated, with the exception of Crenothrix polyspora, which groups apart from other Gammaproteobacteria. The tree was constructed on the basis of 165 amino-acid positions by using TREE-PUZZLE29, a quartet maximum-likelihood method. The support value from 10,000 puzzling steps for the branch to the Verrucomicrobia was 86%. The scale bar represents 0.1 change per amino-acid position.